I'm not sure what you mean to imply here. If you're implying you think I'm Indian and pretending I'm not, well I'm not Indian and I don't follow why you would think that.
If you don’t know, many non-white people get asked that question all the time. That dance you say you can’t imagine, well, it happens quite frequently.
The dialogue being discussed here is about a trait which is not externally evident. It's also a direct question. Where are you really from is more or less directly asking country of origin pre-family immigration however far back that is, which would equate to outright asking someone what their caste is.